In present-day medical treatments, conventional ultrasound diagnostic apparatuses are used for examining and diagnosing various body tissues, such as the heart, liver, kidney, and mammary glands, and these medical image diagnostic apparatuses are advantageous with respect to ease of operability and non-invasiveness as well as being without radiation risks when compared to other medical image diagnostic apparatuses, such as X-ray diagnostic apparatuses and X-ray computed tomography apparatuses.
Ultrasound diagnostic apparatuses usually visualize the morphology of a body tissue by expressing the amplitude of a received signal (echo signal) of an ultrasound wave in luminance. It has been reported in various reports that an echo signal contains various types of physical information, and some of this physical information has clinical applications.
For example, an ultrasound signal with which a subject is irradiated propagates through the subject while attenuating. If the amount of attenuation is large, a phenomenon occurs where the echo signal cannot be received sufficiently. Observation of the characteristics of body tissue by observing such attenuation of an echo signal is often performed and various methods are known in which the amount of attenuation of an echo signal is quantitatively analyzed and then used for diagnosis. However, with the above-described conventional technology, an area that is difficult to reliably analyze may also be analyzed by using the physical information contained in an echo signal.